I struggle with this, personally. I have two small kids, and when they have a fever, etc., they can't go to school or daycare until they are 24 hours symptom free. I don't have any family or friends to watch them, so my husband I usually take turns watching them, or a half day each. Even so, it adds up quickly.
My bosses have been exceptionally understanding, and my pay stub only shows two sick days for the year, although I'm guessing it was closer to ten. I do make an effort to work from home as best I can, maintaining communication with clients, researching projects, etc.
We do have a couple of employees who are absent quite a lot, and there is a lot of discussion about them when they are out. It certainly hampers their chances of advancing, because they are never assigned to large/important projects, as we can't count on their being available at crunch time.
I think that in my company, short of a surgery/major illness, three sick days a year is the acceptable number. But, children's illnesses don't seem to count against that number. (Although, I am the only one with small children who doesn't have a stay-at-home partner, so I am primarily the only one who calls in sick for kids.)